Radio Frequency Identification (RFID) systems comprise tags having thin micro-circuit units with associated antennae. RFID tags may be passive, in that they respond in some fashion to external radio signals, or they may be active, typically in that they are battery powered. The tags have the capacity to provide unique radio signals when interrogated by an appropriate transceiver of the RFID system.
RFID technology is becoming widely used to identify and control the flow of goods, for instance, to identify packages or pallets which are moved in warehouse operations. RFID tags heretofore have been applied to goods in various ways. They may be glued to the article surface, taped, or otherwise merged into the product itself. A typical RFID tag is in the form of a sheet, comprising a flat antenna printed on plastic or paper film and a small micro-processor, or chip, attached to the antenna. A typical tag with pressure sensitive adhesive may be about 0.13–0.15 mm thick at the antenna about 0.3 mm thick at the chip location.
In many instances, it is desirable also to use RFID tags in combination with a label or other marking which is optically readable, by machine means or by human eye, or both, such as would be given by a printed paper or plastic label bearing a bar code. A typical paper or plastic sheet label with pressure sensitive adhesive is about 0.09 mm thick.
A common way of approaching the task of applying a RFID tag with an overlying sheet label to mass production goods, such as molded glass or plastic containers for pharmaceuticals and the like, is to make up an assembly of tag and label, and to then use common bottle labeling equipment. However, the presence of the RFID tag presents special needs. First, the RFID tag is an electronic device and can not be mishandled. Second, the RFID tag must be reliably placed, along with the label. Third, the correlation between the markings on the label and the signature or identification of the RFID tag should be established and verified. The latter is particularly important when the distribution and use of the product is constrained, as is the case for controlled substances (drugs, etc.). There has to be tracking of the RFID tags and labels and means to ensure un-recorded loss of RFID or labels occurs.